Flash video glitch

I would like to apologize for my grammar mistakes first - Iam from Chezch Republic

I have a problem with playing videos in opera 37 (for windows 10) . Flash videos are glitchy, lagging an doing very weird things. Not always, sometimes they work and sometimes i have to use other browsers where everything work fine. I have also tried different settings, reinstalling Opera and Adobe Flash, but it did not help...